package com.yuedou.api.pay.nongshang;

import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

/**
 * @创建者：zhouwei
 * @创建时间：2022/9/22
 * @描述：
 */
public class RSAUtils {

//    公钥>>>  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAg3qGQEbbnGqjKE2ZaQCKFrDXA1kc4wXDNlD/ZjmY8uuKVtB7zmHFF3qUyfoHRT+f3QT7Ss+6b0VP3ayzeTaAQGLBQll4Vo0GHIs7FRs02dtFCyspUj+zLqkm9dvzUVHwNRZPuhz5LBj1rfAT6lNWb5kJBFSKPGO4mvctXd1HNIqxAiIMH1RTeGXnJNsRcnP+DVKrKeCGuHEqX+X97qsJH8xFyDEykpbw/kR7ovLUT43+MGSAZ6AmNN5cIY0/FXrvqg8Nmzc2HWOYQBCBUz3lmBh5yWUAyHFwHGjoNgC5D6Qpl8puxKNeF5diQI6opVsrwANlguzieRfd7H8y/4Ly+wIDAQAB
//    公钥长度>>>  392
//    私钥>>>  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
//    私钥长度>>>  1624

    /**
     * 密钥长度 于原文长度对应 以及越长速度越慢
     */
    private final static int KEY_SIZE = 2048;
    /**
     * 用于封装随机产生的公钥与私钥
     */
    private static Map<Integer, String> keyMap = new HashMap<>();

    /**
     * 随机生成密钥对
     */
    public static void genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器
        keyPairGen.initialize(KEY_SIZE, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        // 得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());

        System.out.println("公钥>>>  "+publicKeyString);
        System.out.println("公钥长度>>>  "+publicKeyString.length());

        // 得到私钥字符串
        String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());

        System.out.println("私钥>>>  "+privateKeyString);
        System.out.println("私钥长度>>>  "+privateKeyString.length());
        // 将公钥和私钥保存到Map
        //0表示公钥
        keyMap.put(0, publicKeyString);
        //1表示私钥
        keyMap.put(1, privateKeyString);
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.getDecoder().decode(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        String outStr = Base64.getEncoder().encodeToString(cipher.doFinal(str.getBytes("UTF-8")));
        return outStr;
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 明文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.getDecoder().decode(str);
        //base64编码的私钥
        byte[] decoded = Base64.getDecoder().decode(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        String outStr = new String(cipher.doFinal(inputByte));
        return outStr;
    }


    public static void main(String[] args) throws Exception {
        long temp = System.currentTimeMillis();
        //生成公钥和私钥
        genKeyPair();
        //加密字符串
//        System.out.println("公钥:" + keyMap.get(0));
//        System.out.println("私钥:" + keyMap.get(1));
//        System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
//
//
//        String message = "RSA测试---->";
//        System.out.println("原文:" + message);
//
//        temp = System.currentTimeMillis();
//        String messageEn = encrypt(message, keyMap.get(0));
//        System.out.println("密文:" + messageEn);
//        System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
//
//        temp = System.currentTimeMillis();
//
//        String messageDe = decrypt(messageEn, keyMap.get(1));
//        System.out.println("解密:" + messageDe);
//        System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
    }
}
